AI algorithm combined with RNA editing-based blood biomarkers to discriminate bipolar from major depressive disorders in an external validation multicentric cohort.

Bipolar disorder (BD) is a leading cause of disability worldwide, as it can lead to cognitive and functional impairment and premature mortality. The first episode of BD is usually a depressive episode and is often misdiagnosed as major depressive disorder (MDD). Growing evidence indicates that peripheral immune activation and inflammation are involved in the pathophysiology of BD and MDD. Recently, by developing a panel of RNA editing-based blood biomarkers able to discriminate MDD from depressive BD, we have provided clinicians a new tool to reduce the misdiagnosis delay observed in patients suffering from BD. The present study aimed at validating the diagnostic value of this panel in an external independent multicentric Switzerland-based cohort of 143 patients suffering from moderate to major depression. The RNA-editing based blood biomarker (BMK) algorithm developped allowed to accurately discriminate MDD from depressive BD in an external cohort, with high accuracy, sensitivity and specificity values (82.5 %, 86.4 % and 80.8 %, respectively). These findings further confirm the important role of RNA editing in the physiopathology of mental disorders and emphasize the possible clinical usefulness of the biomarker panel for optimization treatment delay in patients suffering from BD.

Euthymic and depressed bipolar patients are characterized by different RNA editing patterns in blood.

Bipolar disorder (BD) is a worldwide leading cause of disability. Inflammation roles in this disease is well established. ADAR1-mediated RNA editing is one of the key mechanisms regulating the inflammatory response. We have identified a panel of RNA editing-based blood biomarkers which allowed to discriminate unipolar from BD depression with high accuracy. We confirmed here the diagnostic value of this panel in a new cohort of BD patients recruited in Brazil. We also identified new combinations which allow a clear discrimination of BD from healthy controls and among BD subgroups, confirming that RNA editing is a key mechanism in BD.

A game changer for bipolar disorder diagnosis using RNA editing-based biomarkers.

In clinical practice, differentiating Bipolar Disorder (BD) from unipolar depression is a challenge due to the depressive symptoms, which are the core presentations of both disorders. This misdiagnosis during depressive episodes results in a delay in proper treatment and a poor management of their condition. In a first step, using A-to-I RNA editome analysis, we discovered 646 variants (366 genes) differentially edited between depressed patients and healthy volunteers in a discovery cohort of 57 participants. After using stringent criteria and biological pathway analysis, candidate biomarkers from 8 genes were singled out and tested in a validation cohort of 410 participants. Combining the selected biomarkers with a machine learning approach achieved to discriminate depressed patients (n = 267) versus controls (n = 143) with an AUC of 0.930 (CI 95% [0.879-0.982]), a sensitivity of 84.0% and a specificity of 87.1%. In a second step by selecting among the depressed patients those with unipolar depression (n = 160) or BD (n = 95), we identified a combination of 6 biomarkers which allowed a differential diagnosis of bipolar disorder with an AUC of 0.935 and high specificity (Sp = 84.6%) and sensitivity (Se = 90.9%). The association of RNA editing variants modifications with depression subtypes and the use of artificial intelligence allowed developing a new tool to identify, among depressed patients, those suffering from BD. This test will help to reduce the misdiagnosis delay of bipolar patients, leading to an earlier implementation of a proper treatment.

Phosphodiesterase 8A to discriminate in blood samples depressed patients and suicide attempters from healthy controls based on A-to-I RNA editing modifications.

Mental health issues, including major depressive disorder, which can lead to suicidal behavior, are considered by the World Health Organization as a major threat to global health. Alterations in neurotransmitter signaling, e.g., serotonin and glutamate, or inflammatory response have been linked to both MDD and suicide. Phosphodiesterase 8A (PDE8A) gene expression is significantly decreased in the temporal cortex of major depressive disorder (MDD) patients. PDE8A specifically hydrolyzes adenosine 3',5'-cyclic monophosphate (cAMP), which is a key second messenger involved in inflammation, cognition, and chronic antidepressant treatment. Moreover, alterations of RNA editing in PDE8A mRNA has been described in the brain of depressed suicide decedents. Here, we investigated PDE8A A-to-I RNA editing-related modifications in whole blood of depressed patients and suicide attempters compared to age-matched and sex-matched healthy controls. We report significant alterations of RNA editing of PDE8A in the blood of depressed patients and suicide attempters with major depression, for which the suicide attempt took place during the last month before sample collection. The reported RNA editing modifications in whole blood were similar to the changes observed in the brain of suicide decedents. Furthermore, analysis and combinations of different edited isoforms allowed us to discriminate between suicide attempters and control groups. Altogether, our results identify PDE8A as an immune response-related marker whose RNA editing modifications translate from brain to blood, suggesting that monitoring RNA editing in PDE8A in blood samples could help to evaluate depressive state and suicide risk.

A Pilot Clinical Study on Post-Operative Recurrence Provides Biological Clues for a Role of Candida Yeasts and Fluconazole in Crohn's Disease.

BACKGROUND AND AIMS: This study prompted by growing evidence of the relationship between the yeast Candida albicans and Crohn's disease (CD) was intended to assess the effect of a 6-month course of the antifungal fluconazole (FCZ) on post-operative recurrence of CD. METHODS: Mycological samples (mouth swabs and stools) and serum samples were collected from 28 CD patients randomized to receive either FCZ (n = 14) or placebo (n = 14) before surgical resection. Serological analysis focused on levels of calprotectin, anti-glycan antibodies, and antibody markers of C. albicans pathogenic transition. Levels of galectin-3 and mannose binding lectin (MBL) involved in C. albicans sensing and inflammation were also measured. RESULTS: 1, 2, 3, and 6 months after surgery, endoscopy revealed recurrence in 5/12 (41.7%) patients in the FCZ group and 5/9 (55.6%) in the placebo group, the small cohort preventing any clinical conclusions. In both groups, surgery was followed by a marked decrease in C. albicans colonization and biomarkers of C. albicans pathogenic transition decreased to non-significant levels. Anti-glycan antibodies also decreased but remained significant for CD. Galectin-3 and calprotectin also decreased. Conversely, MBL levels, which inversely correlated with anti-C. albicans antibodies before surgery, remained stable. Building biostatistical multivariate models to analyze he changes in antibody and lectin levels revealed a significant relationship between C. albicans and CD. CONCLUSION: Several combinations of biomarkers of adaptive and innate immunity targeting C. albicans were predictive of CD recurrence after surgery, with area under the curves (AUCs) as high as 0.86. FCZ had a positive effect on biomarkers evolution. ClinicalTrials.gov ID: NCT02997059, 19 December 2016. University Hospital Lille, Ministry of Health, France. Effect of Fluconazole on the Levels of Anti-Saccharomyces cerevisiae Antibodies (ASCA) After Surgical Resection for Crohn's Disease. Multicenter, Randomized, and Controlled in Two Parallel Groups Versus Placebo.

Correction: Brain region-specific alterations of RNA editing in PDE8A mRNA in suicide decedents.

Author forgot to attach a supplementary doc file which includes the supplementary methods and supplementary figure legends.

Brain region-specific alterations of RNA editing in PDE8A mRNA in suicide decedents.

Phosphodiesterases (PDE) are key modulators of signal transduction and are involved in inflammatory cell activation, memory and cognition. There is a two-fold decrease in the expression of phosphodiesterase 8A (PDE8A) in the temporal cortex of major depressive disorder (MDD) patients. Here, we studied PDE8A mRNA-editing profile in two architectonically distinct neocortical regions in a clinically well-characterized cohort of age- and sex-matched non-psychiatric drug-free controls and depressed suicide decedents. By using capillary electrophoresis single-stranded conformational polymorphism (CE-SSCP), a previously validated technique to identify A-to-I RNA modifications, we report the full editing profile of PDE8A in the brain, including identification of two novel editing sites. Editing of PDE8A mRNA displayed clear regional difference when comparing dorsolateral prefrontal cortex (BA9) and anterior cingulate cortex (BA24). Furthermore, we report significant intra-regional differences between non-psychiatric control individuals and depressed suicide decedents, which could discriminate the two populations. Taken together, our results (i) highlight the importance of immune/inflammatory markers in major depressive disorder and suicide and (ii) establish a direct relationship between A-to-I RNA modifications of peripheral markers and A-to-I RNA editing-related modifications in brain. This work provides the first immune response-related brain marker for suicide and could pave the way for the identification of a blood-based biomarker that predicts suicidal behavior.

Emerging RNA editing biomarkers will foster drug development.

Unanticipated adverse drug reactions (ADRs) on the central nervous system are a major cause of clinical attrition and market withdrawal. Current practices for their prospective assessment still lean on extensive analysis of rodent behaviour despite their highly controversial predictive value. Human-derived in vitro models that objectively quantify mechanism-related biomarkers can greatly contribute to better ADR prediction at early developmental stages. Adenosine-to-inosine RNA editing constitutes a physiological cellular process that translates environmental cues by regulating protein function at the synaptic level in health and disease. Robust solutions based on NGS-based quantification of RNA editing biomarkers have emerged to predict the likelihood of treatment-related suicidal ideation and behaviour allowing cost-effective high-throughput drug screening as a strategy for risk mitigation.

In vitro screening for drug-induced depression and/or suicidal adverse effects: a new toxicogenomic assay based on CE-SSCP analysis of HTR2C mRNA editing in SH-SY5Y cells.

Many drugs in clinical trials, or already on the market, can have psychiatric side effects, independently of their therapeutic indication (e.g., Acomplia, Taranabant, and Roaccutane). There is currently no in vitro or in vivo approved test for the detection/prediction of such adverse effects, and the Food and Drugs Administration (FDA) can only issue general alerts on specific therapeutic classes. The development of a screening assay is therefore of real interest. The anti-viral and anti-tumor action of human interferon-alpha (hIFNα) is associated with a variety of neuropsychiatric side effects, including major depression, suicidal ideation and suicide. RNA editing of the serotonin 2C receptor (HTR2C) by adenosine deaminases acting on RNA (ADARs) is a post-transcriptional modification, the regulation of which is altered in depressed suicide victims. In this study, we show that in the SH-SY5Y neuroblastoma cell line, hIFNα specifically activates the ADAR1a isoform and thereby modifies the HTR2C mRNA editing profile. As this hIFNα-induced altered profile partly overlaps with that observed in the brain of depressed suicide victims, we investigated whether it could be used as a signature to identify drugs with depression and/or suicidal side effects. By means of the Biocortech proprietary screening assay, which allows the relative quantification of all the edited HTR2C isoforms in a sample, we blind-tested the effect of 50 marketed molecules on HTR2C mRNA editing in SH-SY5Y cells and identified 17 compounds with an IFN-like editing profile. This new toxicogenomic assay can identify compounds with potential psychiatric adverse events with a positive predictive value of 90 %.